1. Field of the Invention
This invention relates to a novel azo dye, an ink jet recording ink, a heat sensitive recording material, a color toner, a color filter, an ink jet recording method, an ink cartridge and an ink jet printer.
2. Description of the Related Art
Color image recording materials have now come to be the mainstream of image recording materials. Currently prevailing color image recording materials include ink jet recording materials, thermal transfer image recording materials, electrophotographic recording materials, transfer type silver halide light-sensitive materials, printing inks, and recording pens. Color filters are used in displays, such as liquid crystal displays (LCDs) and plasma display panels (PDPs), and solid-state image sensors, such as charge coupled devices (CCDs).
In the color image recording materials described above, while coloring materials (dyes or pigments) of three primary colors for so-called subtractive color mixing system have been used for reproducing or recording full color images, coloring materials having absorption characteristics capable of attaining preferred color reproducing regions and which are fast being endurable to various working conditions have not been yet available at present and improvement therefor has been demanded strongly.
Ink jet recording has been popularized rapidly and will see further development because of low material cost, high speed, low noise, and ease of color recording.
Fundamentally, ink jet recording is divided into a continuous method in which ink droplets are continuously allowed to fly and a drop-on-demand method in which ink droplets are ejected in response to image information signals. The mechanism of drop formation includes a piezoelectric system in which pressure is applied to ink by a piezoelectric element to eject ink droplets, a thermal system in which heat is applied to ink to create bubbles whereby to eject an ink droplet, an ultrasonic system, and an electrostatic system. Ink jet inks include aqueous ink, oily ink, and hot-melt or solid ink.
Colorants used in the ink jet recording inks are required to have good solubility or dispersibility in ink solvents, capability of high-density recording, satisfactory hues, color fastness against light, heat, active gases in the atmosphere (e.g., NOx, oxidizing gases such as ozone, SOx, etc.), resistance against water and chemicals, good fixability on media with minimized blur, stability in ink formulations, nontoxicity, high purity, and inexpensiveness.
It is extremely difficult to obtain dyes that satisfy high levels of these requirements, nevertheless. In particular, there has been a strong demand for colorants with a satisfactory magenta hue that are fast to light and environmental active gases, particularly oxidizing gases such as ozone.
Widely used couplers for azo dyes include phenols, naphthols, and anilines. JP-A-11-209673 and Japanese Patent 3020660 disclose azo dyes with satisfactory hues that are obtained using these couplers, which have turned out to have a disadvantage of poor light fastness. Improvement has been added in JP-A-2001-335714, in which colorants with satisfactory hues and improved light fastness are disclosed. However, all the colorants known by literature have extremely insufficient fastness to oxidizing gases such as ozone.
To develop a dye fast to oxidizing gases such as ozone, the present inventors have reached an idea of using nitrogen-containing heterocyclic compounds as a coupler in place of the related couplers, such as phenols, naphthols, and anilines. Azo dyes prepared from aminopyrazolediazo components and aniline couplers that have hitherto been proposed are disclosed, e.g., in JP-A-55-161856, JP-A-61-36362, JP-A-61-152768, JP-A-6-145543, JP-A-7-224230, U.S. Pat. Nos. 4,650,861 and 4,301,070, and JP-T-11-504958. However, all of them fail to satisfy both hue and various fastness properties. Azo dyes prepared using pyridine couplers are known, including those described in JP-A-51-83631, JP-A-49-74718, JP-A-58-101158, JP-B-52-46230, EP23309, and German Patents 2719079, 2307444, 2513949, 2525505, and 2832020. Azo dyes prepared from pyrazolediazo components and pyridine couplers are proposed in JP-A-2002-371079, WO02/83662. and WO02/83795, which have been proved to have fairly improved fastness to ozone and light but still leave room for further improvement.